exhaust-isms

[ari666]

need mathematical equations from people who know.

[prefaced with:
not interested in 4-1's not interested in buying anything else, wanna work out THIS problem.]

i grabbed a set of crappy rusty extractors off ebay (branded hi-tech), cos my pacemakers got destroyed. it includes extractors, twin 2 inch pipes and a hotdog on either pipe. once i got to the place to pick them up i noticed they were quite a lot smaller all round than my existing system. the primary and secondary pipes are both about 3-4mm smaller, and the tail pipes are 2 inch whereas mine was 2 1/4, joining to 2.5.

i didnt wanna piss the guy off, so i picked up and paid for them like a good ebayer. the problem is i was gonna use these to tie into my existing exhaust, now its looking like i either have to just fit up this whole system, or ditch the idea altogether and waste the cash.

my question is:

1. do i stand to gain/lose/or break even on exhaust flow from smaller pipes, but a twin system.
2. how loud will this system be with just a hot-dog on each pipe? lol. i imagine pretty loud.

[Not_An_Abba_Fan]

What was this system to suit?

[ari666]

he said it was off his 308 'speedway car'

my car is stock stroke 308, carb'd, crane 286 cam, flat tops etc.

[ari666]

this is the difference in primary pipes:


this is the hot dog:


hope it helps

[HoZy]

Just run them, #### the haters

[ari666]

UGH, i need to know!!! im waiting till the stractors' are back on b4 i drop the body back on.

were the old pacies unnecessarily big? all i need to know is that i am not going to strangle my engine with pipes that small.

[Not_An_Abba_Fan]

No, you are not going to strangle the engine. They will be perfectly fine. The 308's ran better with a twin 2" anyway. With those hotdogs it will be pretty loud.

[ari666]

NVM.

just went to fit the passenger side and it doesnt fit... nfi whats going on. i give up. god hates me

[Jonno]

should ask the exhaust dude whos coming ot mine tonite to start making the exhaust for mine :P

well i had straight thru with no mufflers/hotdogs and it was pretty loud, but that stopped at the start of the passanger doors
so im guessing it wouldnt be un bearable

[Not_An_Abba_Fan]

NVM.

just went to fit the passenger side and it doesnt fit... nfi whats going on. i give up. god hates me

Was it a 308 Commodore? If so, they should fit, VB-VK were all the same.

Any chance of posting a pic of the complete extractor?

[ari666]

yeah, the difference was in the starter motor. im using a CVR hi-torque and it was set for the pacemakers, i had to rotate it round to clear these new ones cos' they are a lot tighter to the block (so tight, i am not sure i can get the trans inspection plate back on, but a problem for another day)

while i am here, can i get some opinions on what to do for the system. this is the selection of pipes i have available:


i was thinking of using the two mufflers off the pipes to the far left of pic and the 2 hot dogs. make my own kiss pipe at the front, run the two small mufflers where the stock mufflers usually are, then the two hotdogs out the back. the only thing is the extractors are 2" outlet and every other pipe is either 2.25 or 2.5" will that cause an issue?

these are the headers fitted:

[Jonno]

i recon the 2 with the hotdogs on the pipe (or at least fit them in somewhere and cut a spare pipe and putt a x pipe in between them :P
theen twin thru the rest

[ari666]

i recon the 2 with the hotdogs on the pipe (or at least fit them in somewhere and cut a spare pipe and putt a x pipe in between them :P
theen twin thru the rest

i cant understand this post mate, can you translate to english

[immortality]

smaller pipes will help with low to mid range at the cost of a little bit of peak power. so probably better for a streeter

a twin 2" system will flow more then a single 2.5" i'd go for the twin setup

[ari666]

another couple of q's:

1. should i run a balancer pipe between the 2 pipes? an x pipe is too hard and i cant afford to buy one, so buying ANYTHING is an automatic no., q=balancer pipe yes/no

2: in left of this pic there are two pipes that are exactly the same. there is a 'muffler' on there that has me stumped. it doesnt look like a muffler inside. just has a single 20mm hole and the pipe is straight through. will this work to quieten the noise down? or is it some japanese thing that does nothing. (they are off a skyline)

thank you

[soop]

Wouldnt stress on a balance pipe. People claim a.poofteenth more power with them. Personally think its a wank,

[Not_An_Abba_Fan]

The balance pipe is only there to reduce drone and stop the old school V8 crackle.

The resonator off the Skyline is called a Helmholtz tuner, the hole will have a small section of pipe on it too, it cancels out certain frequencies in the exhaust.

Do you have the tail pipe for the system on the far right? I would use that.

[ari666]

Do you have the tail pipe for the system on the far right? I would use that.

yeah but its only a single 2.5 in/out. this kinda carrys me on to another question, the exhaust as it stands atm is:

extractors to 2" pipe up to those "Helmholtz tuner" things then to 2.5" pipe. i am having trouble figuring out how to get both 2.5" tubes up and over the diff. one idea was to use the rear most muffler (which you just suggested) and bring the two 2.5"s in together just before the diff, so only one goes up and over.

im just wondering what the effects will be of having 2 small pipes (2"), then 2 larger pipes (2.5), then back to 1 larger pipe (2.5) then muffler. obviously i dont expect to be able to build a mind blowing exhaust system from my garage with 0 expierence, but i dont wanna do something which will potentially restrict me (and then have to re-do it later) do it once, do it properley. etc.

[Not_An_Abba_Fan]

Sorry, but you contradict yourself by saying do it once, do it properly, and the try and do it with bits and pieces.

As I said, use that system on the far right. Just bolt it up, don't worry about extra resonators. The twins on the sl/e's had the rh pipe crossing over the top of the diff.

[soop]

Commodore VB VC VH VK 6 Cyl & V8 Sedan Sports Exhaust | eBay

[ari666]

the system on the far right is damaged and is the reason i am going through all this effort. plus it doesnt fit to the new smaller extractors. if it just bolted back on i would have done it by now.

[ari666]

an so buying ANYTHING is an automatic no.

sometimes soop, you are a bit quick to hit that "reply" button

[soop]

No, that was just too far up the thread for me to care.

[ari666]

well if you dont care, then keep your useless links to yourself

[soop]

care/remember :P